The demands for thin bare-die ball grid array (BGA) packages, such as overall stack height reduction and electrical performance improvement have added complexity for thermal solution design, manufacturing, and assembly processes associated with microelectronic packages in computer manufacturing, e.g., in mobile computer systems.
Bare-die packages may include a thermal solution, which during the assembly process applies a load on the dice. This load may be required to achieve thermal performance as very low loads may lead to lower thermal performance. On the other hand, highly concentrated load may cause a die crack risk. The load exerted by the thermal solution is a characteristic of the thermal solution design and the assembly process. The interaction of the thermal solution with the bare-die package during the assembly process may be very critical, creating a need for an in-depth understanding of the impact of design and manufacturing on product quality and performance.
Current thermal solution designs use a thin cold plate, which may be susceptible to significant deflection, when subjected to an enabling load. A deflection or tilt of a cold plate may easily cause a concentrated load to apply to the dice or other substrate components (e.g., passive components, package stiffener, etc.), which may result in die damage, solder joint reliability or electrical shorts, as well as product performance impact due to degraded thermal contact between the dice and cold plate. Further, current thermal solution designs may be provided by third party manufacturers, who may not always adhere to thermal performance and mechanical pressure requirements of semiconductor package manufacturers.